H-52 1ST U.S. R/C FLIGHT SCHOOL Loop P 1/4 Loop 1/4 Square Half rs-o Combos Cross-box HS III PHASE DAS Cross-box Maneuver Combinations DAS Theaerobatic box , outside of competition, is the reasonable airspace that a pilot performs his PHASE III maneuvers in with good visibility. Theperformance zone is the smaller airspace within the aerobatic box where the visibility and presentation is the best, but requiring that the maneuvers be performed closer together to stay within it. The advanced aerobatic pilot uses all the airspace within the performance zone by performing maneuvers parallel to both the X and Y axes. Maneuvering on the (cross-box) Y axis at the advanced level typically consists of performing two maneuvers to effect a turnaround at either end of the field, while at the same time repositioning the airplane toward the front or rear of the performance zone. The following pages contain some of the most complimentary maneuver combinations on the Y axis that also effect a turnaround. Aerobatic Box X axis Y axis Mid-field Center Box Y axis Performance Zone X axis 1/4 1/4 Slow roll Hammerhead Humpty bump Side note: The airplane’sflight path is judged R/C pilots who have not yet acquired the rudder in radio control aerobatics, whereas the attitude knowhow to prevent wind drift. Students of X of the airplane is primarily judged in full-scale. Precision Aerobatics who know how to prevent Consequently, without being allowed to “crab” wind drift, can use the Y axis to make room for noticeably into a crosswind, a full-scale airplane certain maneuvers and to improve their viewing Loop Positioning center ends up drifting downwind while maneuvering. perspective. For example: To avoid having to box maneuvers Thus, a set of maneuvers on the Y axis are strain looking up, looping maneuvers are better Roll for better viewing designed into each competition sequence to viewed some distance out beyond the pilot, perspectives. re-position the plane to the upwind side of the whereas a slow roll is better viewed closer in. box. This practice will also prove helpful for H-53 KPTR: Maneuvering on both the X and Y axes increases the room to maneuver while maintaining good visibility. Cross-boxTurnaround Combination: Humpty to a Hammerhead DAS PHASE III The Y axis turnaround combination of a humpty bump and hammerhead work well together, and are ideally suited to set up any center (aerobatic box) maneuver that requires a higher entry speed. “one two Each of these maneuvers favor high entry speeds “one two Roll one” and finish at high speed. Therefore, this combi- nation works equally well with the humpty bump before or after the hammerhead, and can be per- one two” formed to reposition the airplane either to the front or rear of the aerobatic boxC depending on which direction the plane is rolled in the first maneuver. 1/4 1/4 Roll Right 3 Half Pull-pull-pull humpty bump: Enter the humpty roll roll Left 3Roll bump parallel with the runway.3 roll on the up- roll line in the direction that you want to fly across the box. Pull over the top, and perform a half roll on the downline to set up a cross-box pullout to level flight. one” Hammerhead: Perform the hammerhead with a 3 “one roll on the downline to exit heading back toward the center of the aerobatic box. Increase the throttle to build up sufficient airspeed for the next maneuver before or during the pullout, not after. KPTR: The first in a series of maneuvers should set up the speed and altitude for the next. H-54 Cross-box Combination: Hammerhead to a Humpty DAS PHASE III The Y axis turnround combination of a hammerhead followed by a humpty 1/4 bump makes quite an impression. Hammerhead: Enter the hammer- “one two Roll one” head parallel with the runway. 1/4 Perform a3 roll on the downline to set up a cross-box pullout to level “one two Roll one” flight. One has the option to perform Pull-pull-pull humpty bump:¼ roll a3 roll on the upline of the on the upline in the direction that you hammerhead: Roll so that intend to pull over the top. In this the top of the plane is facing example, that will be to your left the front of the box for the Right 3 roll (toward the center of the aerobatic Left easiest perspective through Half 3 box). Pull over the top, and perform roll roll the remainder of the upline a half roll on the downline to exit and the pivot. heading back toward the center of the box. Option Note: Establishing level flight be- 1/4 tween maneuvers provides a moment “one Roll one two” of respite to begin anticipating what 1/4 is next and to ensure that the wings are levelC along with being an impor- tant competition requirement and a stamp of proficiency. KPTR: A proficient pilot establishes a definite level H-55 end to the first maneuver before entering the next. Cross-box Combination: Pull Humpty to a Push Humpty DAS Back-to-back humpty bumps PHASE III on the Y axis work well to- gether, and are made more interesting by pulling over 1/4 the top of the first humpty, and pushing over the top of 1/4 the second. Pull-pull-pull humpty bump: “one two Roll one” 3 roll on the upline in the direction that you want to fly across the box. Pull over one two” Note: If considerable rudder the top with right rudder. is applied trying to correct a Perform a half roll on the deviation from vertical at the downline to set up a cross- point of initiating the pull box pullout to level flight. or push over the top, that Half Left Right roll 3 roll rudder will likely have to 3Roll roll Pull-push -pull humpty:3 - be maintained and will take roll the airplane into position precedent over the usual to push over the top toward P-factor rudder corrections. the center of the box. Push I.e., “pull-right. -- - push-left”. over the top with left rudder, at slower speeds only works and hold the downline for a on a consistent basis when “one Roll one two” few counts before pulling out. “one the pull or push starts with the wings level after a truly vertical upline. KPTR: Anticipating which way to roll and push or pull stems from routine wings level entries and perfect verticals. H-56 Half Square Loop Setup to a Spin DAS The following page contains a Y axis turnaround combination requiring PHASE III a higher altitude setup to a spin. Every aerobatic pilot should be familiar with using the Immelmann turnaround to gain altitude. The turnaround that To spin advanced pilots use to more precisely control just how much altitude is gained is the half square loop. Note: While a spin can be set up in any direction, it is much easier to keep within the performance zone when set upinto the wind. Therefore, the half square loop turnaround should be performed downwind of center box. Half square loop 1. Approach the entry at high speed, full power, with the wings perfectly level. Pulling to the upline should be smooth, but completed quickly, in order to minimize the chance of a deviation occurring during the pull. You also have the option to 2. Maintain full power to improve controllability and tracking once you perform a half roll on the get to the top. And unless there is a strong contrary crosswind, look for upline of a half square loop, and expect to need increasing amounts of right rudder at some point and then push to upright along the upline to counter the increasing effects of slipstream. flight. 3. Approaching the targeted altitude, assuming the upline is truly vertical, “one two three four” smoothly pull elevator with increased right rudder to cap off at the top Option inverted. One can then maintain inverted flight to set up an inverted spin, or roll upright to set up an upright spin. Side note: With all the twisting and turning going on at this point, should there be any question about the direction to apply the rudder when a devia- tion from vertical is first detected, knowledge of the increasing effects of slipstream along an upline should provide assurance that right rudder will correct it. However, keep the rudder input initially small and watch the plane closely, just in case it has to be switched for whatever reason. (FYI: The battle to correct the upline after it was entered without level wings will be greater than battling a 20 mph direct crosswind!) H-57 KPTR: Counting on the upline will help you consistently match the right altitude to the number of spin revolutions that will follow. Cross-box Combination: Upright Spin to a Hammerhead DAS A popular Y axis turnaround combination is the PHASE III 13 -turn upright spin followed by a hammerhead. Here, a 23 -turn spin is performed to afford the pilot a little more time to anticipate the spin’s Left upright spin cross-box recovery. A23 -turn spin set up parallel with the runway will exit cross-box in the same direction the spin was initiated (into the wind typically). You “one two “one” should avoid initiating a spinwith the wind, since the wind will displace the entry and cause it to 1/4 1/4 appear barrel-rolled or prematurelyforced! If there Cross-box is no crosswind component to the wind, one’s only concern is to initiate the spin in the direction that you want to be heading after the spin.